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A218213
Number of n-digit primes representable as sums of consecutive squares.
2
1, 4, 13, 30, 69, 187, 519, 1401, 3889, 10861, 31640, 90735
OFFSET
1,2
COMMENTS
There are no common representations of two, three or six squares for n < 13, so
a(n) = A218207(n) + A218209(n) + A218211(n); n < 13.
FORMULA
a(n) = A218214(n) - A218213(n-1).
MATHEMATICA
nn = 8; nMax = 10^nn; t = Table[0, {nn}]; Do[k = n; s = 0; While[s = s + k^2; s <= nMax, If[PrimeQ[s], t[[Ceiling[Log[10, s]]]]++]; k++], {n, Sqrt[nMax]}]; t (* T. D. Noe, Oct 23 2012 *)
KEYWORD
nonn,base
AUTHOR
Martin Renner, Oct 23 2012
STATUS
approved